From 7d971661e902b81a6b3f760b10d42c0b65e9cd29 Mon Sep 17 00:00:00 2001
From: Mark Abraham <mark.j.abraham@gmail.com>
Date: Fri, 17 Nov 2017 11:58:39 -0700
Subject: [PATCH] Add checking function for whether a buffer is pinned

This is useful for several kinds of tests proposed.

Change-Id: If9fdd29e73f16299190b5485f473f6388aab9ec9
---
 src/gromacs/gpu_utils/gpu_utils.cu | 25 +++++++++++++++++++++++++
 src/gromacs/gpu_utils/gpu_utils.h  |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/src/gromacs/gpu_utils/gpu_utils.cu b/src/gromacs/gpu_utils/gpu_utils.cu
index 5e0afd3f2b..fb509f5d37 100644
--- a/src/gromacs/gpu_utils/gpu_utils.cu
+++ b/src/gromacs/gpu_utils/gpu_utils.cu
@@ -134,6 +134,31 @@ static void checkCompiledTargetCompatibility(const gmx_device_info_t *devInfo)
     }
 }
 
+bool isHostMemoryPinned(void *h_ptr)
+{
+    cudaPointerAttributes memoryAttributes;
+    cudaError_t           stat = cudaPointerGetAttributes(&memoryAttributes, h_ptr);
+
+    bool                  result = false;
+    switch (stat)
+    {
+        case cudaSuccess:
+            result = true;
+            break;
+
+        case cudaErrorInvalidValue:
+            // If the buffer was not pinned, then it will not be recognized by CUDA at all
+            result = false;
+            // Reset the last error status
+            cudaGetLastError();
+            break;
+
+        default:
+            CU_RET_ERR(stat, "Unexpected CUDA error");
+    }
+    return result;
+}
+
 /*!
  * \brief Runs GPU sanity checks.
  *
diff --git a/src/gromacs/gpu_utils/gpu_utils.h b/src/gromacs/gpu_utils/gpu_utils.h
index ad2297eae0..8f59630462 100644
--- a/src/gromacs/gpu_utils/gpu_utils.h
+++ b/src/gromacs/gpu_utils/gpu_utils.h
@@ -242,5 +242,8 @@ void resetGpuProfiler(void) CUDA_FUNC_TERM
 CUDA_FUNC_QUALIFIER
 void stopGpuProfiler(void) CUDA_FUNC_TERM
 
+//! Tells whether the host buffer was pinned for non-blocking transfers. Only implemented for CUDA.
+CUDA_FUNC_QUALIFIER
+bool isHostMemoryPinned(void *CUDA_FUNC_ARGUMENT(h_ptr)) CUDA_FUNC_TERM_WITH_RETURN(false)
 
 #endif
-- 
2.22.0